The present invention relates to control apparatus for a pneumatically operated hopper feeder.
In many manufacturing and packaging processes, it is required to provide a supply of particulate material. One conventional supply system employs a pneumatically operated hopper feeder. In the usual form of apparatus, material is drawn, along with entraining air, into a hopper body to which a vacuum is applied. When a given weight of material has been filled into the hopper body, the body which is supported on a resilient suspension, becomes displaced downwards sufficiently to actuate a normally closed pilot valve. On actuation, this valve causes the vacuum on the body to be released and the filling operation stops. The release of vacuum allows a one-way valve on the bottom of the body to open, and the body dumps its contents and is raised upwards by the suspension. The normally closed pilot valve is deactuated and vacuum is re-applied to the body. The cycle can then repeat itself.
An example of the above-described apparatus is illustrated in U.S. Pat. No. 3,186,768, in the name F. P. Pendelton, dated June 1, 1965.